When Fighting Monsters
by Kenophobia
Summary: It's early season 10 and Dean is a demon. When Sam fails to capture his brother on his first attempt, he'll have to try a different strategy to get his brother back, even if it means sacrificing his own humanity.
1. Chapter 1

Sam shook his head and blinked his eyes, trying to clear the smog from both. As his vision focused, he squinted up to see Dean fighting the man that had captured him earlier, Cole. It suddenly dawned on him that Cole hadn't dropped those keys by accident. Sam had been allowed to escape, so that he could be followed.

It wasn't much of a fight. The would-be assassin may not have believed Sam's earlier warnings that he was out of his depth, but he was sure getting the picture now. Sam watched as Dean pinned Cole up against a car, hitting him repeatedly, pressing the first blade up against his throat. Sam almost turned away; he did not want to watch his brother murder this man. Unlike Cole, he had known what he would be walking into, but seeing his brother like this, as one of the creatures which they both despised, made him feel sick to his stomach. Pulling himself together, he pulled out some holy water and the handcuffs, trying to decide if it was worth compromising his mission to try and save this man's life. However, before he could make up his mind, he realized that Dean wasn't actually going to kill the man, he was walking away. Sam felt a small flair of hope, perhaps his brother wasn't completely gone after all.

Seeing his opportunity, Sam grabbed his flask of holy water and flung its contents at Dean who snarled in pain and dropped to one knee. Sam went for his brother's wrist with the handcuffs but before he could put them on, he found himself thrown backwards by a sudden blast of telekinetic force. Oh great, his least favourite demon trick. He struggled to get to his feet, still dazed and unable to use his right arm for balance. Slowly, Sam pulled out the demon killing knife and held it in front of him. He had no intention of using it to deliver a killing blow, but at this point he didn't have a lot of options for defending himself.

Dean sauntered towards him casually, a smile on his lips. "That's funny Sam, I was just about to say the same thing to you."

Sam lunged forwards with the knife, Dean deflected the attack, but didn't press one of his. "He's playing with me" thought Sam, "just like he was with Cole." Sam attacked again, but with only one arm to strike with, he was unable to break through Dean's defence. Desperate, Sam feigned a blow with his left arm, but at the second transferred the blade to his injured right. Sam's shoulder screamed in agony he swung out with his bad arm. Taken by surprise, Dean didn't move fast enough to block. Unfortunately, Sam was unable to put much force behind the blow, and Dean was left only with a shallow cut across his ribs. Just like it had with Cole, being injured finally seemed to provoke Dean to go on the offensive. He grabbed Sam's bad arm and twisted, and Sam was forced to drop the knife as he yelled in pain. Then Dean, obviously much stronger now, physically threw him across the alleyway.

This time, Sam found himself unable to get up as Dean walked towards him. He was still trying when he noticed another figure behind Dean. It was Cole. He had obviously regained consciousness at some point and was now picking up the demon killing knife which Sam had dropped. Sam watched the sunlight glint off the blade as Cole swung it in an overhand strike and plunged it straight into Dean's back.

"No!" yelled Sam in a panic as Dean sank to his knees in front of him. His mind screamed in rejection of what he was seeing. No, this couldn't happen, he wasn't going to watch Dean die in front of him all over again, not after finally finding him. Yet despite his denial, he was still surprised as Dean got slowly to his feet and turned around to face his would-be killer. His eyes completely black, Dean reached up and pulled the knife from between his own shoulder blades. It fell to the pavement with a clatter. Then Dean rushed forward with inhuman speed and the next thing Sam knew Cole's head was rolling away from his body and Dean was continuing to strike at his body with the first blade, just as he had done with Abbadon. Sam knew then that he had no chance of subduing his brother that day by force or otherwise, and also no choice but to get out of there and regroup. With Dean still distracted, Sam staggered to his feet and ran.

* * *

When Sam got back to the bunker, Castiel was there waiting for him. The angel took in Sam's battered face and defeated expression and knew without asking what the outcome of his mission had been. Not sure how to comfort the younger Winchester, Castiel did what he had seen Dean do before in times of great emotional distress. He grabbed a couple of beers from the fridge and passed one over to Sam, who took it with a grimace. He didn't open his own of course, he knew that even with his powers failing, he still had enough grace to not be able to taste it properly. So, he just sat there and let Sam tell his story.

"and then he killed him, and I ran" Sam finished. Castiel could see how tired he was. His shoulders were so sloped he was probably only sitting at half his full height and his voice held that air of hopelessness that Castiel had come to associate with and impending apocalypse.

"So, the knife did nothing" Castiel said.

"Not quite nothing. It seemed to hurt him, but he still healed pretty quickly."

"I suppose that shouldn't be too surprising. Cain was the leader of the Knights of Hell and they could not be killed with ordinary weapons. Even angel blades were virtually useless against them."

"Then we have nothing" Sam sighed, but this time Castiel could hear a note of determination in his voice and he knew that the hunter would not be giving up on his brother.

* * *

Late that night, or maybe early the next morning, Sam was still sitting at that table. He was long past exhausted, but he refused to sleep until he had come up with a plan to save Dean. Castiel had left a few hours earlier with his friend Hannah. With his grace failing, the two of them had set out on a mission to find some way of helping the dying angel. Sam didn't blame them, he knew that Cas couldn't help right now anyway, and he needed to be thinking about saving his own life, but losing his only ally left him feeling more alone than ever.

Sam sat in the dark, going over every way he knew of to stop a demon. Exorcism wouldn't work because Dean wasn't possessed. Trapping him in a devil's trap somehow was a possibility, but if anyone knew all the old hunting tricks well enough to avoid them, it was Dean. One by one, Sam thought over all of the powerful demons they had faced together over the years, he thought through every scenario, trying to decide if he could apply it to the current problem, and eventually he arrived at a conclusion. There was only one solution, one way he knew of to subdue a powerful demon, immune to most weapons, without necessarily having to kill it. After hours of getting nowhere, the plan came to him now in a rush. He was going to need to find more demons, and not for information this time. No, this time Sam needed something very specific from them: their blood. It was time to revive a long-buried habit.


	2. Chapter 2

As Sam walked into the bar, he couldn't help thinking of all the times he had been in similar dives with Dean. For reasons that had always eluded him, his brother seemed to love places like these. Places with dingy lighting, battered upholstery, and cheap beer. It was just the kind of place that attracted desperate people at the end of their ropes, and tonight, that was just what Sam was counting on. He took a seat at the bar next to a blonde woman in her mid thirties. He didn't do this kind of thing very often, but Sam knew that women considered him attractive, it wasn't long before the woman, plied by alcohol and a pretty face, was telling him her whole life's story.

"And now my ex is trying to get my kids taken away. I've poured most of my money into legal fees, but he's still kicking my ass in court. It's a mess." The blonde woman, Sadie, tossed back another shot.

"You know" said Sam, "there might actually be something I can do to help."

"What are you a lawyer or something?"

"Or something" Sam smiled.

* * *

Less than an hour later, Sam was standing at the nearest crossroads watching Sadie bury a box in the dirt.

"Okay, now all you have to do is say these words", he handed her a piece of paper, "and tell the person who appears what you want. I'll be right over there, okay?"

Sadie nodded determinedly, and Sam moved to stand a few paces away. He had no intention of actually letting a deal go down. This time he was going to be faster. When a man with a grey beard and a black suit suddenly appeared in the middle of the road, he immediately charged, tackling the man and rammed the demon killing knife into his shoulder. He heard a shriek come from Sadie, followed by the sound of her heels clacking against pavement as she ran away, but he was much too preoccupied to look up. Before the demon pinned underneath him had time to retaliate, Sam lowered his head and bit into its neck.

* * *

The next morning, Sam rolled out of bed feeling hopeful for the first time in weeks. The demon blood produced a high in him similar to the comfortable, free feeling that came from the rare occasions in which he indulged in too much alcohol. However, unlike alcohol, the blood didn't leave him feeling hung over in the morning. Actually, he felt great, better than he had in weeks. Even his arm was barely bothering him anymore. Reaching the kitchen, he got himself out some cereal and reached past the bottle of demon blood in the fridge to grab the milk. As he ate, he scrolled through the news on his computer, mentally going over his plans for the day. Not even the headline "Questions pile up in the investigation of former marine's, murder" could sour his mood.

His breakfast done, Sam began to get out the ingredients for the summoning. Powerful demons like Crowley had a specific summoning ritual associated with them. They could choose whether or not to actually show up, but Sam was betting that after seeking his help in getting rid of the newest knight of hell, Crowley was going to be willing to take his call. After failing to capture Dean on the first opportunity, Sam hadn't wanted to contact the king of hell until he was holding a few more cards. It was never a good idea to negotiate from a place of weakness, but now with the demon blood in his veins, Sam was ready and feeling anything but weak.

" _Et ad congregandum . . ."_ Sam chanted.

"Moose" Crowley spoke, appearing suddenly, "I've been expecting your call. No doubt you asked me here to beg for my help again."

"Think again Crowley, its me that's cleaning up your mess, and all I need from you is his location."

"Straight to the point then. Well, I'd help you if I could, but unfortunately, I don't know where he is."

"Sure, you don't" Sam scoffed. "Do you really expect me to believe that you haven't got your people watching him?"

"I did, but he managed to find and kill all of them. I am curious though, after failing so miserably the first time around, what exactly is your master plan for bringing home brother dearest?"

"This." Fed up with Crowley's mocking and realizing he wasn't going to be of any help, Sam focused his mind and reached out to grab onto the demonic soul that was inhabiting the body in front of him. He mentally wrestled with the soul, but Crowley was a powerful demon and resisted him. Realizing he wasn't powerful enough yet to take on a high-level demon, Sam was forced to relent. He let go of the struggling soul, and both he and Crowley were left gasping like they had run a marathon.

"Well, well Moose" Crowley practically purred. "That is an impressive party trick. Seems like you haven't got quite enough juice yet though."

"Yeah well, give me time." Sam sounded almost petulant.

"Oh, I'm going to give you far more than that. Moose you should have come to me in the first place. I'd heard of your blood junkie mojo before of course, but if I'd seen it in action, well, we needn't have even bothered with the whole Mark of Cain thing, I should've just sicced you on Abbadon."

Sam felt a resurgence of guilt. Could they have avoided all of this mess if he had just started drinking sooner? He was beginning to forget why he had ever stopped.

"Ah well, better late than never" Crowley sighed dramatically, "and when it comes to demon blood, who better to have as your dealer than the King of Hell? Back in a jiffy", and with that he disappeared, leaving behind the faint smell of sulfur.

That was not how Sam had expected the conversation to go. Fortunately, he didn't have long to dwell on his confusion because within ten minutes, Crowley was back again, carrying a large glass vat like the kind used to ferment wine, only it wasn't filled with wine. "Here we go, hot off the tap" said the demon cheerily. "Now, I can't tell you where that pesky brother of yours is at this exact moment, but I can equip you to take him off both of our plates when you do finally catch up with him."

Sam wasn't sure what to say, he didn't trust the demon, but this would be a lot easier than having to keep tricking other people into summoning crossroads demons for him. Finally, he settled on "when I do get him back we're both coming after you next."

"Yeah, yeah, I know the line. Just, do give me a ring when you need more blood won't you? Oh, and Sam, if you ever feel like a career change, I think you'd make a lovely crossroads demon. You're better at talking humans into selling their souls than half the demons I have on staff." With that he disappeared again. Sam walked over and began to haul the jug of blood towards the to the cold pantry.

* * *

Dean drove through the night on an almost empty highway, just like he had done countless times before, but this time all that was next to him in the front seat were some balled up fast food wrappers. He didn't know where he was going, and he didn't know what he was going to do when he got there. He was just driving, unable to shut down the debate that kept cycling over and over through his head. He was a hunter, he was supposed to save people. That instinct was so ingrained in his mind that even becoming a demon hadn't shut it down completely, but he also wanted to kill, wanted it desperately, knew it was what he was meant to do. Fortunately for Dean's peace of mind, that old do-gooder voice in his head seemed to be getting quieter as time went on. Maybe he would just keep driving until it shut up altogether.


	3. Chapter 3

Graham took another sip of his beer and smiled at the woman perched on the bar stool next to him. She was talking about her thesis or something and most of it was going completely over his head, but as long as he smiled and nodded now and then, Nora didn't seem to notice. The night had been going well. Graham had sat in a corner booth for almost an hour, nursing a beer and pretending to watch the baseball game while really watching the pretty brunette. It had taken him that long to work up the nerve to approach the beautiful woman, but now that he had, and she was actually talking to him, he was feeling pretty confident that the night might get even better.

"After I do my defense in June, I'm going to apply for this post-doc position in California" Nora said.

"Hmm, yeah, California is great" murmured Graham, idly wondering what a post-doc was.

"Yeah, if you like spray-tanned hipsters and overpriced sushi."

Graham jerked his head up, suddenly fully present. Some guy in a flannel shirt was leaning against the bar to the other side of Nora, grinning casually like they were all best friends. Graham disliked this intruder immediately; the other man was attractive, if slightly drunk, and obviously rude enough to not care that he was interrupting a private conversation. He was still mentally expostulating on the stranger's deficiencies, when he realized to his dismay that Nora was laughing at the man's comment.

"Well, I guess everywhere has its downsides, but Stanford is one of the top academic centres in the country."

"Stanford hey? My baby brother went there." The man settled onto a stool clearly not planning on leaving anytime soon. "I'm Dean by the way."

"Nora" Nora replied, and Graham wondered how he could tell this Dean guy to get lost without seeming like a territorial ass.

"Umm, Nora and I were actually talking, so . . ." Graham attempted lamely.

"Yeah, I could see you were talking, but now we're talking" the guy spoke in a low, almost threatening voice.

Now Graham had had enough. It wasn't everyday that a guy got this far with a woman like Nora and he wasn't about to let some random drunk loser ruin it for him. Buoyed on by irritation and two and a half bud lights, Graham walked around behind Nora and grabbed the other man's arm in a decidedly non-friendly way. He barely had time to realize that he'd made a mistake before he found himself pressed up against the bar with a hand around his throat as Nora gave a surprised squeak and backed away quickly. Graham struggled as hard as he could, but Dean held him down easily with one unrelenting, vice-like hand. Flailing his arms out in a panic Graham was relieved when his fingers made contact with his almost empty beer bottle. He swung it as hard as he could to smash it against his attacker's head. To Graham's dismay, the other man barely reacted at all to the blow except to squeeze his hand even tighter around his neck. As darkness began to creep in around the edges of his vision, Graham could almost have sworn that the man's eyes looked entirely black.

* * *

Dean felt someone grab him from behind, probably a bouncer, and try to pull him away from the man whose life was slowly slipping away in his hand. He ignored it. Just a moment longer and . . . yes, there it was, Dean could sense the moment the man died, his soul detaching itself from the body and floating until it could be picked up by a reaper and sent to its final destination. Only then did he turn around casually to stare down the beefy man behind him. The bouncer lurched backwards, reacting to Dean's black eyes, and Dean reached for the first blade. His hunger for destruction, now awoken, was far from sated.

Dean spun around and stabbed the bouncer through the centre of his sternum, pausing only a second to watch the man gurgle blood before pulling the blade free again. There was no point in taking his time with this kill, not when he could already see a group of men, who had previously been playing a rowdy game of pool, charging towards him, apparently intent on being heroes. The men were still a couple of feet away when Dean raised his hand in their direction, and not sure exactly how he was doing it, pushed out with his mind. The three men flew backwards through the air and slammed painfully into the wall behind them. Dean grinned to himself, it sure felt good being on the other end of that for a change.

In the moment of calm that followed, Dean heard the breathy sound of a woman whispering. His attention snapped to Nora, now crouched down on the sticky floor and trying to hide behind a vinyl booth. Her mascara was running down her face and her words were hard to make out through her sobbing, but it didn't take a genius to figure out who she was calling on the cell phone she was clutching in her shaking hands. Dean strode over to her and knocked the phone from her varnished fingers. The woman shrieked a little and tried to scramble away from him but didn't make it far enough to be out of the reach of the first blade. Dean scowled in annoyance as he looked down at the newly dead grad student. He had been thinking about reviving some of the skills he had learned from Alastair, it had been so long since he had gotten to use any of them, but now the police were most likely on their way, and he had to finish things quickly. Sighing, he turned back to the centre of the room and prepared to get to work.

* * *

Dean walked out of the bar several minutes later feeling more alive than he had in years. No more anguished moralizing, no more internal debate, he was finally at peace. As he strolled past the dilapidated sign for the Black Goat Bar towards where he'd parked Baby, Dean actually hummed to himself. The familiar notes of AC/DC the only thing breaking the silence of the cool night air.

* * *

Sam woke up gasping. He struggled to catch his breath as the bright and bloody images faded from his head. It had been a long time since he'd had one of his prophetic dreams, many years, but he still remembered what they felt like. Now, even though he could already feel the vision's after-burn forming into a migraine, he had never been so happy to have one. It had been 18 days since he had summoned Crowley and the vat of demon blood was two thirds empty, but he still hadn't been able to track down his wayward brother. Now, after weeks of scouring the news for demonic omens or grisly murders, of chasing down even the thinnest lead, he didn't have to search at all. He knew exactly where Dean was going to be.


	4. Chapter 4

Dean had come to the bar with no particular plans other than to consume enough whiskey that if he were still human, we would have been struggling to walk straight. Just another shit hole bar in another shit hole town, but as he signaled the bartender for another round and the usual buzz stubbornly failed to kick in, he found himself getting more and more bored and restless. He looked around him at the bar's other patrons; once you'd been to enough places like this, you started to feel like you were seeing the same people over and over again, and Dean had always been good at reading people. There was the group frat boys playing an obnoxiously loud game of pool, the woman in a too tight t-shirt with the bad dye job, the old alcoholic who never looked up from the bottle in front of him, and a little way down the bar, his usual target, the attractive grad student. Unfortunately for Dean, this particular specimen was already talking to a bland looking man in a polo shirt. Normally, this would have been enough to cause Dean to back off, but tonight he wandered over anyway and sidled up to the pretty brunette.

"Hmm, yeah, California is great" polo shirt mumbled in response to something the woman had said.

"Yeah, if you like spray-tanned hipsters and overpriced sushi" Dean butted into the conversation and was rewarded by a giggle from the brunette.

"Well, I guess everywhere has its downsides, but Stanford is one of the top academic centres in the country."

"Stanford hey? My baby brother went there." Dean settled onto a stool and turned on his most charming smile. "I'm Dean by the way."

"Nora" She replied.

"Umm, Nora and I were actually talking, so . . ." polo shirt finally spoke up, clutching his half empty beer in front of him like some kind of talisman.

"Yeah, I could see you were talking, but now we're talking" Dean snarled in his direction. He turned back to Nora, dismissing the other man entirely and was surprised when he felt someone grab his arm. Apparently, polo shirt had more balls than Dean had given him credit for. No matter, teaching him a lesson would make the evening even more fun. Dean spun around and reached with one hand for the other man's throat, but before he could reach it, a strong grip closed around his wrist, blocking him. He looked up in surprise as a tall figure stepped between him and the cowering stranger.

"Hello Dean" Sam said.

* * *

Sam stepped in front of his brother, relieved that he had been in time to stop the slaughter he had witnessed in his dream.

"Sam" Dean spoke in an overly friendly tone "imagine running into you here of all places. I wasn't sure I'd be seeing you again so soon after our last meeting."

Sam ignored him, let Dean waste his time with stupid banter, he was here to get a job done and he wouldn't be distracted. It was a good thing too, because Dean moved in almost too quickly to follow, aiming a punch at Sam's head. Sam barely managed to dodge and backed off trying to put some distance between them.

"Hey! Take it outside!" someone, probably a bouncer, yelled. They both ignored him.

His brother lunged at him again, his eyes black with rage, but before he could get close, Sam activated his powers, pushing back against the charging demon. Dean lurched to a stop, shock evident on his face. He blinked confusedly a few times before seemingly figuring it out.

"Blood, Sammy? And here I thought you'd kicked that nasty habit."

Sam continued to ignore him, tightening his mental grip on the swirling mass of evil that was all that was left of his brother's soul. He heard Dean growl with pain and anger, but it was as though he was hearing everything from a long way off, so intent was he on maintaining his psychic hold. The demon thrashed trying to break free, but Sam was well prepared, he had guzzled what had seemed like gallons of Crowley supplied blood before coming here. Still, he felt a trickle of blood slid down his lips from his nose as he struggled to hold his brother in place. Dean was evidently much stronger than a regular demon, the only other demon to give Sam so much trouble had been Lilith herself.

Normally, this would have been the point at which Sam either pulled the demon free from its host, exorcising it, or simply killed it with his mind, however, in this case he couldn't do either. Instead, he reached to pull out the handcuffs he had brought with him from the bunker. These handcuffs, the same ones they had used on Crowley, were one of the Men of Letter's most useful inventions, once in place, they would strip away the powers of even the most powerful demon, making them no more of a threat than any ordinary human. Sam moved forward and clapped them around Dean's wrists, blood practically pouring from his nose as he fought to maintain his concentration on immobilizing Dean while doing up the handcuffs at the same time. When the cuffs finally snapped in place, Sam released his mental hold with a gasp, almost collapsing from exhaustion and blood loss.

Barely a second later he felt a chain wrap around his neck and realized too late that relaxing had been a mistake. What Sam had neglected to remember, was that even without demon powers, Dean Winchester was still pretty damn dangerous. Sam felt his lungs gasp for air and his head go heavy as Dean wrapped the chain of the handcuffs around his brother's throat from behind. Weakened from his psychic battle, Sam struggled futilely as darkness creeped in around his peripheral vision. Just when he was about to pass out, Sam heard a faint smashing noise and the pressure around his throat slackened.

Pushing Dean off him Sam heaved himself to his feet. Standing in front of him was a rather unimpressive looking man in a polo shirt clutching the neck of a broken beer bottle in one hand. Sam looked down at his now unconscious brother and saw blood matting the back of his head where a bottle had been slammed into it. "Thanks" Sam said hoarsely. The man stared at him with a terrified expression on his face and mumbled something about black eyes.

Stooping down, Sam hauled Dean up and dragged him into the parking lot. He felt a little bad about locking his brother in the trunk of the Impala but putting him on the back seat would just be stupid; he might wake up and try to strangle him again. Walking around to the front of the car, Sam got in and began the long drive home.

* * *

When Dean came to, he found himself chained up in a devil's trap, in a familiar dungeon, with Sam starring down at him. He rattled his chains a little, but it was more for show than in attempt to break free, Dean knew that was useless.

"Well, Sammy, what happens now?" he asked resignedly.

"Now I cure you" Sam said jabbing a needle into his own arm and filling it with dark red blood.

Dean laughed. "Been confessing your sins, have you? Begging forgiveness for all that nasty blood drinking?" Sam tried to look stoic, but Dean could tell the words were affecting him. "Sorry Sammy, but I don't think that's going to work."

"And why not?" Sam asked, "It was working on Crowley."

"Because the demon curing ritual requires purified human blood" Dean said, savouring the moment, "and yours is anything but pure. Haven't you noticed Sammy, that since our little spat in the bar, your eyes have been just as black as mine."


End file.
